This invention pertains to a magenta inkjet ink comprising a combination of certain pigment colorants. The invention also pertains to a process of making the magenta inkjet ink and an inkjet ink set comprising this magenta ink.
Inkjet printing is a non-impact printing process in which droplets of ink are deposited on a substrate, such as paper, to form the desired image. Inkjet printers are equipped with an ink set which, for full color printing, typically comprises a cyan, magenta and yellow ink (CMY). An ink set also commonly comprises a black ink (CMYK). Colorants for the inks can be soluble in the ink vehicle (dyes) or insoluble (pigments).
Pigment Red 122 (PR122) is the most often used magenta pigment colorant. Pigmented inkjet ink sets comprising Pigment Red 122 as the magenta colorant are disclosed, for example, in U.S. Pat. Nos. 5,085,698; 5,738,716; 6,153,000 and 6,395,079. An improved magenta pigment colorant should compare favorably with PR122 in terms of optical density and chroma.
Magenta inkjet inks comprising Pigment Red 146 as the magenta colorant are disclosed, for example, in U.S. Pat. Nos. 5,328,504; 6,680,355 and 6,332,943.
Magenta inkjet inks comprising Pigment Red 184 as the magenta colorant is disclosed, for example, in U.S. Patent Application Publication No. 2003/0167965.
While various known magenta inkjet ink colorants, both pigment and dye, provide printed images having good color characteristics, a need still exists for alternative colorants with higher optical density, chroma and/or lower cost. The present invention satisfies this need by providing compositions having improved optical density, chroma, hue and cost.